180 PHILOSOPHICAL THOUGHT. 



JErkenntnisstheorie, the theory of knowing, or Epistemo- 

 logy. All these recent developments, however much 

 they may differ amongst each other, have this in 

 common, that they are an outcome of the modern critical 

 spirit, of that professedly free and unprejudiced inquiry 

 into the historical, logical, and psychological foundations 

 of the whole structure of knowledge and belief as it 

 has grown up in history or as it presents itself to 

 individual minds. Criticism, in fact, had at this stage 

 arrived at the study of fundamentals and origins. 

 With these it is still everywhere occupied, without any 

 immediate prospect of arriving at such tolerable 

 unanimity as would secure the foundation for any 

 generally acceptable system of philosophy. 



The study of origins and fundamentals at which the 

 process of critical examination had thus arrived about 

 the year 1860 met with great encouragement and 

 support from two independent lines of research which 

 had their beginning within the region of the exact and 

 natural sciences. These were started by the appearance, 

 ei. in 1859, of Darwin's 'Origin of Species,' and by the 



Influence of 



Darwin and posthumous publication, in 1868, of Eiemann's disserta- 



Riemann. * 



tion (written already in 1854) on the ' Hypotheses of 

 Geometry.' The latter was immediately followed by 

 Helmholtz's equally important paper on the " Data 

 which lie at the Foundation of Geometry." In fact, the 

 study of origins and fundamentals had been taken up by 

 men of science independently of the critical movement 

 in philosophical and historical thought, and contributed 

 very largely to the strengthening of the critical move- 

 ment. For a moment the hope existed that here at 



